Broadband services amongst small businesses and home consumers are increasing at a rapid pace. Consistent with this trend is the proliferation of broadband devices which increase end users' capabilities and functionalities, e.g., voice over Internet Protocol (“VOIP”) devices. Thus, it is common for an end user to have multiple network devices coupled to a single broadband connection (interface) having only one wide area network (“WAN”) Internet Protocol (“IP”) address. In order to facilitate easy addition of such devices, many broadband devices contain a Dynamic Host Configuration Protocol (“DHCP”) server, to lease out IP addresses, as well as a Network Address Translation Device or “NAT” device, which provides a means for private/local IP addressing. The DHCP functionality combined with NAT features provides a plug and play router for an end user to couple multiple other network devices which the end user wishes to reside on the network. A broadband device containing a DHCP server, and a NAT device is referred to herein as a “gateway-router device”. In addition, a gateway-router device may contain other application specific functionality, e.g., VOIP functionality.
A gateway-router device is conventionally connected to a WAN via a broadband interface, such as a cable modem, for example. The gateway-router device sits as an intermediary between the broadband interface and a plurality of network devices. (Please note that alternatively the broadband interface and gateway-router device may be integrated into one device.) In operation, the gateway-router device has both a WAN side (port 1) and a local area network (“LAN”) side (port 2). (Please note that many gateway-router devices may have multiple physical ports on the LAN side, however, these multiple physical LAN side ports are all interconnected to one logical LAN port with a unique address (port 2).)
On the WAN side, the gateway-router device communicates with the WAN, via the broadband interface, typically using the single WAN IP address, made known to the gateway-router device from the broadband interface. On the LAN side, the gateway-router device is interconnected with the plurality of network devices which the end user wishes to utilize on the network. Such network devices may include a personal computer(s) (“PC”), file server(s), web server(s), printer(s), gaming device(s)/controller(s), etc. (hereinafter referred to as “LAN devices” for simplicity of explanation).
Upon request from a LAN device, the gateway-router device's DHCP server provides a private (or LAN) IP address to each requesting LAN device. Such private addresses may be leased from the gateway-router device in a wide range of schemes such as random; sequential order, based upon the sequential order of requester; etc.
Thus, for example, if an end user has two LAN devices, namely a web server and a client PC, if the web server requests a private address first, it will be given a first sequential private IP address, 192.168.1.2 (for example). If the client PC is the next requester, it will be given the next sequential private IP address, 192.168.1.3 (for example). (The gateway-router device will give its LAN port the first address in the private address space, 192.168.1.1, in this example.) Thus, private addresses are leased out by the DHCP server and translated by the NAT, thereby giving LAN devices their own network identity, yet enabling them to access the WAN without conflicting with each other.
The above configuration works in perfect harmony, from a routing point of view, until a second gateway-router device is added. If a second gateway-router device is introduced into a network which already has a first gateway-router device (where the WAN side of the second gateway-router device is communicatively connected to the LAN side of the first gateway-router device), there exists the possibility of conflicting private addresses. It is important to note that the address space ranges for private addresses have been pre-defined by The Internet Assigned Numbers Authority (“IANA”) to a finite group. Currently that finite group comprises the following three blocks: 10.0.0.0; 172.16.0.0; 192.168.0.0.
In conventional systems, if the first gateway-router device leased out private addresses in the address space of 192.168.X.X, there is nothing preventing the second gateway-router device from leasing out private addresses in the same private address space. Thus, in current systems, it is possible, for a first gateway-router device and a second gateway-router device to lease out the same private addresses to different devices, e.g., leasing out private address 192.168.1.3 to two (2) different LAN devices (one LAN device interconnected to the first gateway-router device, and another LAN device interconnected to the second gateway-router device). Therefore, in current network topologies, where two gateway-router devices co-exist, there is a potential for misconfiguration and communication problems if multiple DHCP servers of each gateway-router device in a network, respectively, are simultaneously attempting to provision IP addresses in the same private address space.
What is needed is a device, system and method to prevent the simultaneous provisioning of private IP addresses in the same private address space by multiple gateway-router devices residing on the same LAN.